Properties of Antisera to Glutamate Dehydrogenase from Nitrogen-fixing Lupin Nodules

Abstract

Antibody prepared in rabbit to lupin (Lupinus luteus) nodule glutamate dehydrogenase (GDH) crossreacted with all six isozymes of GDH isolated from lupin nodules. Rocket immunoelectrophoresis showed that the antisera were also strongly cross-reactive with GDH from other parts of the lupin plant and from the roots and stems of other leguminous plants and wheat, but not with GDH of Rhizobium lupini, lupin bacteroids or bovine liver. This confirms the exclusively plant origin of lupin nodule cytosolic GDH. Enzyme activity, determined spectrophotometrically, was strongly inhibited by the antibody. Substrates and modifiers of GDH did not influence the degree of this inhibition, indicating that the antiserum should be an effective reagent for study of the localization of GDH in plants.